Spin torque transfer technology, also referred to as spin electronics, which is based on changing magnetic state of the system by momentum transfer to conduction electrons, is a recent development. The digital information or data, represented as a “0” or “1”, is storable in the alignment of magnetic moments within a magnetic element. The resistance of the magnetic element depends on the moment's alignment or orientation. The stored state is read from the element by detecting the component's resistive state.
The magnetic element, in general, includes a ferromagnetic pinned layer and a ferromagnetic free layer, each having a magnetization orientation, and a non-magnetic barrier layer therebetween. The magnetization orientations of the free layer and the pinned layer define the resistance of the overall magnetic element. One particular type of such elements is what is referred to as a “spin tunneling junction,” “spin torque memory”, “spin torque memory cell”, and the like. When the magnetization orientations of the free layer and pinned layer are parallel, the resistance of the element is low. When the magnetization orientations of the free layer and the pinned layer are antiparallel, the resistance of the element is high. The magnetization orientation is switched by passing a current either parallel across the layers or perpendicularly through the layers.
At least because of their small size, it is desirous to use spin torque memory cell elements in many applications, such as random access memory. However, their small size also creates issues.
One problem is an excessive heat generation caused by the use of currents with high amplitude to switch the magnetization orientation of the memory cells. Among other things, this temperature increase reduces the stability of the magnetic elements. Another problem is a relatively long typical switching time (e.g., many nanoseconds) of such elements.